JP3528364B2 - Laser beam synthesizing apparatus, synthesizing method, laser engraving apparatus, and laser engraving method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser plate making apparatus and a laser plate making method for producing a printing plate used in gravure printing, and the present invention is not limited to these and relates to a laser beam combining apparatus and a combining method.

[0002]

[Prior art]

[Laser Plate Making Apparatus] First, general items of the laser plate making apparatus related to the present invention will be described. The laser plate making apparatus is also called an electronic gravure system plate making apparatus, and is an apparatus for making a printing plate (intaglio) used at the time of gravure printing.

Conventionally, in gravure printing, a metal plate is used as a printing plate (intaglio plate) used for printing, and the metal plate sheet is made up of a set of minute recesses by photolithography of the image density and the etching technique. A two-dimensional halftone image plate was formed. In the next printing stage, the printing plate is dipped in an ink reservoir, and then excess ink is scraped off and pressed onto the paper surface to complete printing. Gravure printing is widely used because it can easily print hundreds to thousands of sheets.

In recent years, an electronic gravure technique using a resin sheet as a printing plate has been put into practical use. This laser plate making apparatus is an apparatus as shown in FIG. 8 and uses a laser beam to form recesses corresponding to the light and shade of an image on a resin sheet of a printing plate. The resin sheet of the printing plate has a surface layer coated with a thermoplastic resin such as modified polyester.

As shown in FIG. 8, a laser plate making apparatus generally has a plate body 1 which is driven to rotate about an axis 4 (in the direction A or B) as a main scanning unit, and a semiconductor laser (LD).
And the laser block portions 10 and 21 including the optical system, and the laser block portions 10 and 21 in the axial direction of the plate cylinder 1 (C
Direction or D direction). A resin sheet 2, which is a workpiece, is wound around the plate body 1.

The main scanning unit comprises a plate cylinder unit 1, a plate cylinder rotation driving motor 7, and the like. The plate cylinder 1 is drivingly connected to a plate cylinder rotation driving motor 7 via a plurality of timing belts 5 and a plurality of pulleys 6, and is rotationally driven in the A direction or the B direction.

The laser block units 10 and 21 will be described later.

The sub-scanning portion is connected to a laser block moving motor 24 and a rotor (not shown) of the motor 24, and is bridged in the axial direction of the plate body portion 1 between bearing portions 23R and 23L. The ball screw 26, the moving element 27 screwed to the ball screw 26, etc., and the laser block moving motor 24 rotationally drives the ball screw 26, and the rotational movement of the ball screw 26 is converted into the linear movement of the moving element 27. The laser block unit 1 (on the laser block mount 28) connected to the mover 27 that moves linearly via an arm 29.
0, 21 is a track that is extremely accurately defined by two rails 22 and is parallel to the axial direction (in the C direction or D direction).
Moving.

(Operation of Laser Plate Making Apparatus) The operation of the above laser plate making apparatus will be described. FIG. 9 is a block diagram of the main functions of the laser plate making apparatus of FIG.

The microcomputer (CPU) 32 is
Controls the operation of the entire laser plate making device. Image data of an image to be printed is stored in a data RAM 38 connected to the CPU 32. For color printing, for example,
C (cyan), M (magenta), Y (yellow), BK
This is (black) digital image data or the like.

Gamma table 4 connected to the CPU 32
Reference numeral 2 is a non-linear conversion table stored in, for example, a ROM. The CPU 32 compares the image data 40 stored in the data RAM 38 with the gamma table 42, and determines the concave portion having a shape corresponding to the image data 40 to the resin sheet 2
The value of the output relationship between the laser intensity and the emission time required for forming the above is determined. That is, the value of the output relationship of the laser intensity and the light emission time corresponding to the data of each pixel of each plate of C (cyan), M (magenta), and Y (yellow) is determined. If necessary, B (black) printing plate data is also included.

A rotation control signal is sent from a microcomputer (CPU) 32 to a plate cylinder rotation driver (plate cylinder rotation drive device) 35. From the rotation control signal, the plate cylinder rotation driver 35 drives the plate cylinder rotation motor. A driving pulse signal is sent to 7, and the plate cylinder 1 rotates stepwise in synchronization with this driving pulse. On the other hand, the CPU 32 determines the laser intensity and the light emission time according to the gamma table 42 from the image data stored in the data RAM 38, and sends this data to the laser driver (laser driving device) 43.

The laser driver 43 sends a pulse signal corresponding to this data to the semiconductor laser 10 to cause the semiconductor laser 10 to emit light in synchronism with the drive pulse of the plate cylinder rotating motor 7, and the irradiation spot on the resin sheet 2 is irradiated. The resin is melted and scattered and sublimated to form a predetermined recess on the resin sheet 2. The semiconductor laser 10 sequentially forms recesses corresponding to image data along the circumference of the resin sheet 2 wound around the plate cylinder 1. The spot shape of the laser is typically a square shape of about 50 [micron], and the depth of the concave portion formed on the resin sheet is 5 to 6 [micron], which is irradiated according to the gradation of the image. .

A movement control for forming a concave portion corresponding to an image until the plate cylinder 1 makes one rotation, and moving the laser block portions 10 and 21 by one pixel in the axial direction of the plate cylinder 1 in synchronization with the end of one rotation. Motor driver for moving the laser block 3
3, the laser block moving motor 24 is rotationally driven to move the laser block units 10 and 21.

In this way, while rotating the plate cylinder 1 to form a concave portion for one rotation, and thereafter, the operation of moving the laser blocks 10 and 21 by one pixel is repeated to form an image on the resin sheet 2 having a predetermined area. To form a concave portion corresponding to.

As described above, the laser plate making apparatus synchronizes the rotation of the plate cylinder 1 by the plate cylinder rotating motor 7 and the linear movement of the laser block portions 10 and 21 by the laser block moving motor 24 while the semiconductor laser 10 is being synchronized. Is a device for forming a set of concave portions corresponding to image data on the resin sheet 2.

(Conventional Laser Beam Optical System) FIG.
It is a figure which shows the principal part of the laser beam optical system built in the laser block parts 10 and 21 of the conventional laser plate making apparatus used for such a laser plate making apparatus. The laser block unit includes the semiconductor laser 10 and the optical system 21. In the optical system 21, a collimator lens 50, an anamorphic prism 51, an objective lens 52, and a cover glass (CG) 53, which are arranged adjacent to the semiconductor laser 10, are sequentially arranged in a hollow body along the optical axis.

A laser beam is emitted from the semiconductor laser 10, collimated by a collimator lens 50, beam-shaped by an anamorphic prism 51, focused by an objective lens 52, and wound on a plate cylinder portion 1. The desired image is formed.

FIG. 11 is a diagram showing an actual configuration of such a laser beam system. The semiconductor laser 10 is an LD (la
ser diode) Holder 61, collimator lens 50 is held by collimator lens holder 60, anamorphic prism 51 is held by anamorphic prism holder 63, and objective lens 52 is held by objective lens holder 64. .

[0020]

The laser beam currently used in the laser plate making apparatus is a single laser beam source (single beam), and is an average for forming concave portions on, for example, an A3 size printing plate. It requires 40 minutes of working time. For this reason, it is required among users to shorten the plate making time.

As one approach to shortening the plate making time, the applicant has already proposed a multi-beam type laser plate making apparatus in which a plurality of laser sources are arranged around the plate cylinder in the circumferential direction or the rotation axis direction. did.

FIG. 12 is a diagram showing the overall configuration of a multi-beam type laser plate making apparatus already proposed by the applicant of the present application. The multi-beam method shown in FIG. 12 has four laser blocks 10A and 21A, 10B and 21B, 10
C and 21C, 10D and 21D are fixed on the same laser block mount 28, and are integrally moved along the rail 22. Here, the laser blocks 10A and 21
A is a partial area A of the plate-making area of the resin sheet 2, laser blocks 10B and 21B are areas B, laser blocks 10C and 21C are areas C, and laser block 10 is
D and 21D are configured to respectively take the region D and form a recess.

This multi-beam method is effective for shortening the plate-making time by reducing the plate-making area of each laser beam source, but it is a boundary part between regions irradiated by different laser sources in one plate cylinder. There is a problem that it is very difficult to adjust the (joint). That is, the position adjustment of each laser head needs to be performed in units of several microns, and the optical adjustment and output adjustment of each laser head are also required to be delicate. As a result, at present, there are subtle differences in the recesses formed by the laser heads, a uniform finish cannot be expected over the entire printing plate, and it is difficult to completely eliminate the joints in the irradiation area. Plates with such joints cannot be used for gravure printing.

Therefore, in view of the above problems, it is an object of the present invention to shorten the plate making time in a laser plate making apparatus.

A further object of the present invention is to provide a laser plate making apparatus which shortens the plate making time in the laser plate making apparatus and has no local unevenness in quality over the entire finished printing plate.

Further, according to the present invention, when the laser plate making apparatus is separated,
In general, it is also an object to provide a laser beam synthesizing apparatus and a synthesizing method.

[0027]

The present invention proposes to utilize four laser beams by utilizing the difference in wavelength in addition to the polarization direction. This plate-making device includes first and second semiconductor laser devices that emit a laser beam having a wavelength λ1 and first and second semiconductor laser devices that collimate the respective emitted laser beams of the first and second semiconductor laser devices. Collimator lens, first and second anamorphic prisms for respectively shaping the emitted laser beams of the first and second collimator lenses, and polarization planes of the laser beams from the second anamorphic prism. A first half-wave plate that rotates the first half-wave plate, and a first polarization beam splitter that combines the laser beam from the first anamorphic prism with the laser beam from the first half-wave plate. And third and fourth semiconductor laser devices for emitting a laser beam having a wavelength λ2,
The third and fourth collimator lenses for collimating the emitted laser beams of the third and fourth semiconductor laser devices, respectively, and the emitted laser beams of the third and fourth collimator lenses are shaped, respectively. Third and second anamorphic prisms, a second half-wave plate for rotating the polarization plane of the laser beam from the fourth anamorphic prism, and a laser beam from the third anamorphic prism And a second polarization beam splitter for combining the laser beam from the second half-wave plate, a combined laser beam of wavelength λ1 emitted from the first polarization beam splitter, and the second polarization beam splitter. Dichroic mirror for synthesizing a synthetic laser beam of wavelength λ 2 emitted from And an objective lens for focusing the combined laser beam al emitted the focused combined laser beam to form a to form a recess by irradiating the resin sheet plate. With such a configuration, four laser beams can be used due to the difference in polarization direction and wavelength.

[0028]

[0029]

The present invention can also be understood as an invention of a plate making method. Further, the technical idea of the present invention can be understood as a laser synthesizing apparatus and a laser synthesizing method, apart from the plate-making apparatus and the plate-making method.

[0031]

[One Example of Laser Plate Making Apparatus]

(Main Part of Laser Beam Optical System) FIG. 1 is a diagram showing a main part of a laser beam optical system of an embodiment of a laser plate making apparatus. In this embodiment, paying attention to the polarization direction of the laser beam, the laser beams from the two laser beam sources are combined so that the recesses at the same position of the resin sheet can be formed. Is increased to shorten the plate making time, and at the same time, a concave portion of uniform quality is formed over the entire plate.

As shown in the figure, along the optical axis OA-A of the laser beam from the semiconductor laser 10A, the collimator lens 50A, the anamorphic prism 51A, the polarization beam splitter 55AB, the objective lens 52 and the cover glass 53 are They are arranged one after another in a serial relationship. Of these, each optical element except the polarization beam splitter 55AB is shown in FIG.
The semiconductor laser 1 of the conventional laser beam optical system shown in FIG.
0, the collimator lens 50, the anamorphic prism 51, the objective lens 52, and the cover glass 53, respectively. For convenience of description, this will be referred to as a “route A” laser beam, and reference numerals of the optical elements in the figure will be identified by adding “A” to the reference numerals.

A route B of the laser beam is formed so as to be orthogonal to the laser beam of the route A. That is, as shown in the figure, above the polarization beam splitter 55AB, along the optical axis OA-B of the laser beam from the semiconductor laser 10B,
Collimator lens 50B, anamorphic prism 5
1B are sequentially arranged in a serial relationship. This laser beam is referred to as "route B". Similarly, the reference numeral is identified by adding "B".

As shown in the figure, each optical element is route A
The optical axis OA-A of the laser beam is orthogonal to the optical axis OA-B of the laser beam of the route B at the position of the polarization beam splitter 55, and the optical axis OA-A and the optical axis OA-B of the route B are arranged so as to coincide with each other.

First, each optical element of "route A" will be described. The semiconductor laser 10A is, for example, a near-infrared laser diode, and has a maximum output of 2 at the current commercial level.
It is a high-power semiconductor laser that emits TAPS (tapared stripe) in [W] and has a laser beam wavelength λ of 780 to 830 nm. The laser beam emitted from the semiconductor laser 10A is P-polarized and enters the collimator lens 50A.

Here, “P-polarized light” generally means that the vibration direction of the electric vector of the light incident on the sample surface is within the incident surface (the surface including the normal to the sample surface and the wavefront radiation (the traveling direction of the beam)). The included right-angled polarized light is "S-polarized light", which is the opposite.
Generally, the vibration direction of the electric vector of the light incident on the sample surface is the incident surface (the normal to the sample surface and the wavefront radiation (the traveling direction of the beam)).
Is a right-angled polarized light that is perpendicular to the plane including the two, and the two have an orthogonal relationship.

The collimator lens 50A has a predetermined focal length, and collimates the laser beam from the semiconductor laser 10A into parallel light with respect to the optical axis OA-A (collimation).
Making all of the beams parallel to each other. ) Is an optical element that acts to The collimator lens 50A can be moved in the direction of the optical axis by an appropriate moving means (not shown).

Anamorphic prism
rizm Also referred to as “anamorphic prism”. )
Reference numeral 51A is an optical element for shaping the beam shape, and is therefore an optical element that acts so as to produce images having different vertical and horizontal magnifications on the image plane. The anamorphic prism 51A is made up of two 3
Prismatic prism (hereinafter referred to as "triangular prism")
The bottom surfaces of 51A-1 and 51A-2 are attached to an aluminum base plate, and the top and bottom surfaces of this triangular prism are right-angled triangles. As can be seen from FIG. 1, the laser beam emitted from the collimator lens 50A is
It is incident on the hypotenuse side surface of the triangular prism 51A-1, refracted and emitted from the height side surface. And further, the triangular prism 51A
The light enters the −2 slope side surface, is refracted, and exits from the height side surface toward the polarization beam splitter 55AB.

Polarizing beam splitter (PBS polarizat
The ion beam splitter) 55AB is an optical element that splits into two light fluxes using a birefringent crystal, and acts so as to transmit the incident P-polarized light or reflect the incident S-polarized light in the direction of 90 degrees.
Therefore, the P-polarized laser beam from the anamorphic prism 51A passes through the polarizing beam splitter 55AB and goes toward the objective lens 52.

The objective lens 52 has a predetermined focal length and focuses the light beam of the P-polarized laser beam from the polarization beam splitter 55AB onto the resin sheet 2 surrounded by the plate cylinder 1 to form a predetermined concave portion. To form.

In the case of the laser beam of the route A, the laser beam optical system operates similarly to the conventional laser beam optical system described with reference to FIG. 10, and the polarization beam splitter 55AB acts as a transmission.

Next, the "route B" will be described. Route B semiconductor laser 10B, collimator lens 50B
The anamorphic prism 51B is the same as the semiconductor laser 10A of route A, the collimator lens 50A, and the anamorphic prism 51A described above, respectively.

Similarly, the laser beam emitted from the semiconductor laser 10B is P-polarized and the collimator lens 5
It is incident on OB.

The collimator lens 50B acts so that the light beam of the laser beam from the semiconductor laser 10B becomes parallel to the optical axis OA-B. The collimator lens 50B is
It can be moved in the direction of the optical axis OA-B by a suitable moving means (not shown).

In the anamorphic prism 51B, the laser beam emitted from the collimator lens is incident on the oblique side surface of the triangular prism 51B-1, refracted and emitted from the height side surface. Then, the light further enters the inclined side surface of the triangular prism 51B-2, is refracted, exits from the height side surface, and goes toward the half-wave plate 54.

Unlike the route A, the half wave plate 54 is arranged on the route B. The half wave plate 54
It is an optical element composed of an electron-optical birefringent plate that rotates the plane of polarization of a laser beam. The half-wave plate 54 rotates the P-polarized laser beam incident from the anamorphic prism 51B into S-polarized light, and the polarization beam splitter 5
Turn to 5AB.

As described above, the polarization beam splitter 55
AB is an optical element that acts to transmit P-polarized light or reflect S-polarized light in the direction of 90 degrees. Therefore, the S-polarized laser beam from the half-wave plate 54 is reflected by the polarization beam splitter 55 in the 90 ° direction, and the objective lens 52 is reflected.
Directed to. Here, the optical elements of the route A and the route B are relatively positioned so that the optical axis OA-B of the route B is aligned with the optical axis OA-A of the route A and has the same optical axis OAAB thereafter. Has been done.

Similarly, in the objective lens 52, the resin sheet 2 in which the light beam of the S-polarized laser beam from the polarization beam splitter 55AB is wrapped around the plate cylinder 1 (not shown).
Focus on (not shown).

In the laser beam optical system shown in FIG.
Semiconductor laser 10A and route B semiconductor laser 10
The laser beam emitted from both B is the resin sheet 2
Focus on the same spot above. By thus concentrating the laser beam of route A and the laser beam of route B at the same location, the laser beam of route A and the laser beam of route B are equivalent to the conventional single laser beam of FIG. 10 (equivalent to only route A). The laser beam of high intensity is focused on the resin sheet 2 (workpiece), and the plate making speed is increased. In addition, since the concave portion is formed over the entire resin sheet by using one synthetic laser beam, the problem of joints unlike the multi-beam method does not occur, and uniform quality can always be ensured.

The following method is available for concentrating the route A laser beam and the route B laser beam. (1) The laser beams of two routes are emitted at the same timing. (2) The laser beams of two routes are emitted alternately.
With this method, the semiconductor lasers 10A and 10B can be cooled alternately, and the life of the semiconductor lasers can be extended. (3) The laser beam of one route is mainly used and the laser beam of the other route is used subordinately. For example,
The normal-sized concave portion uses the main laser beam, and the relatively large-sized concave portion uses the two main and sub-route laser beams. Which method is adopted is appropriately determined according to the required quality of gravure printing, the allowable work time, and the like.

(Structure of Laser Beam Optical System) FIG. 2 is a diagram showing an actual structure of the laser beam optical system of FIG.
The semiconductor lasers 10A and 10B are LD blocks (laser
diode blocks) 62A and 62B, respectively. The collimator lenses 50A and 50B are held by the collimator lens holders 60A and 60B, respectively. Two anamorphic prisms 51A and 51B
And half-wave plate 54 and polarization beam splitter 55AB
And are integrally held by the anamorphic prism holder 63.

(Concept of Laser Beam Optical System) FIG. 3 (1)
Is a conceptual representation of the laser beam optical system of the above embodiment. In the embodiment shown in FIG. 1, the two laser beams are combined by focusing on the difference in their polarization planes. That is, route A
Then, the P-polarized light from the laser beam emitting means 10A is incident on the beam combining means 55AB including a polarization beam splitter. In the route B, the laser beam emitting means 10B
After changing the P-polarized light from the S-polarized light into S-polarized light by the polarization plane rotating means 54 composed of a half-wave plate, the beam combining means 55AB
Incident on. The beam combining means 55AB combines these laser beams having different polarization planes.

The laser beam emitting means 10A, 10
Depending on the characteristics of the laser beam emitted from B, etc., means 50A, 50B for collimating the laser beam and means 51A, 51B for shaping the laser beam are provided in the preceding stage of the beam combining means 55AB, respectively. Beam converging means for converging the combined beam as required is provided after the means 55AB.

[Embodiment of Laser Plate Making Apparatus According to the Present Invention] (Four Laser Beam Optical Systems) FIG. 4 is a diagram showing a main part of a laser beam optical system of an embodiment of the laser plate making apparatus according to the present invention. In this embodiment, focusing on the difference in polarization direction and the difference in wavelength, the laser beam is divided into four routes A, B, C, and D.
Combining two laser beams.

Here, the routes A and B are wavelengths λ1.
By using the laser beam of No. 2 and the laser beam of wavelength λ2 different from the wavelength λ1 for the routes C and D, the routes A and B and the routes C and D are separated according to the wavelength. For example, each wavelength λ1 of routes A and B may be the shortest wavelength 780 nm of the semiconductor laser 10 currently used,
Each wavelength λ2 of routes C and D may be the longest wavelength 830 nm.

The upper half of FIG. 4 shows the route A of the laser beam.
And B are shown, and the laser beam optical system is the same as that of the embodiment described with reference to FIG. 1 except that the dichroic mirror 56 is arranged at the subsequent stage of the polarization beam splitter 55AB.

The dichroic mirror 56 is an optical element that reflects the laser beam according to the wavelength and does not relate to the vibrating surface. A P-polarized laser beam (wavelength λ 1) from the anamorphic prism 51 A of route A and an S-polarized laser beam (wavelength λ 1) from the half-wave plate 54 B of route B
The combined laser beam of 1) is the dichroic mirror 56.
To the objective lens 52.

The routes C and D of the laser beam in the lower half of FIG. 4 will be described. Laser beam routes C and D
Is the same as the one in which the routes A and B of the laser beams in the upper half of the figure are rotated by 90 degrees, except that the wavelengths of the semiconductor lasers 10C and 10D are .lambda.2.

As described above, the dichroic mirror 56
Is an optical element that reflects the laser beam according to the wavelength and does not relate to the vibrating surface. The P-polarized laser beam (wavelength λ 2) from the anamorphic prism 51C of the route C and the half-wave plate of the route D The S-polarized laser beam (wavelength λ2) from 54D becomes a combined laser beam by the polarizing beam splitter 55CD, goes to the dichroic mirror 56, is reflected by the dichroic mirror 56, and is combined with the combined laser beam from the polarizing beam splitter 55AB to be the same. It goes toward the objective lens 52 along the optical axis.

As described above, the semiconductor lasers 10A, 10
The laser beams emitted from B, 10C and 10D are focused on the resin sheet 2. By focusing the laser beams of route A to route D, as compared with the conventional single laser beam of FIG. 10 (corresponding to route A only),
A larger laser intensity can be obtained with the resin sheet 2 (workpiece). Further, since the four laser beam sources form one combined laser beam on the resin sheet 2 (not shown), concave portions of uniform quality are formed over the entire printing plate, and problems such as joints do not occur. .

There are the following methods for concentrating the laser beams of routes A to D. (1) The laser beams of four routes are emitted at the same timing. (2) Laser beams of four routes are sequentially emitted alternately or divided into two groups and emitted alternately. With this method, it is possible to secure a time for cooling the semiconductor lasers 10A to 10D, and it is possible to extend the life. (3) A laser beam of any one or two or more routes is mainly used, and a laser beam of the remaining route is used as a slave. For example, a normal-sized recess uses a main laser beam, and a relatively large-size recess uses two main and sub-route laser beams. Similarly, any one is appropriately selected according to the required specifications of the printing plate.

(Method of Changing Image Forming Size of Resin Sheet) In the above-described embodiment, the corresponding optical elements of each route are the same. However, by making the corresponding optical elements different between the routes, for example, by making the focal length of the collimator lens 50A of route A in FIG. 1 relatively longer than that of the collimator lens 50B of route B, the size of the image to be formed is increased. By setting the size to a normal size for the route A and a relatively small size for the route B, a double image can be formed on the resin sheet 2 as shown in FIG. 3B. This makes it easier to adjust the optical axis between routes,
In addition, the accuracy of adjustment can be reduced. Similarly, also in the case of the embodiments having the routes A to D shown in FIG. 4, the focal lengths of the collimator lenses 50A to 50D can be made different so that the image sizes can be made different from each other, if desired.

(Concept of Laser Beam Optical System) FIG. 5 conceptually shows the laser beam optical system of the embodiment of FIG. In the embodiment of FIG. 4, attention is paid to the difference in the wavelengths of the laser beams, and further attention is paid to the difference in the polarization planes of the two laser beams within the same wavelength, and they are combined. That is, routes A and B
The wavelength λ1 is used in the above, and the wavelength λ2 is used in the routes C and D. Within the same wavelength, attention is paid to the plane of polarization as described with reference to FIG.

In route A, the laser beam emitting means 10
The P-polarized light of wavelength λ1 from A is made incident on the beam combining means 55AB composed of a polarization beam splitter. In the route B, the P-polarized light having the wavelength λ1 from the laser beam emitting means 10B is changed to the S-polarized light by the polarization plane rotating means 54B composed of a half-wave plate, and then is incident on the beam combining means 55AB. The beam combining means 55AB combines these laser beams having different polarization planes.

In route C, the P-polarized light of wavelength λ2 from the laser beam emitting means 10C is made incident on the beam combining means 55CD which is a polarization beam splitter. In the route D, the wavelength λ2 from the laser beam emitting means 10D
The polarization plane rotating means 5 composed of a half-wave plate for the P-polarized light
After being changed to S-polarized light in 4D, it is incident on the beam combining means 55CD. The beam combining means 55CD combines these laser beams having different polarization planes.

The outputs from the beam synthesizing means 55AB and the beam synthesizing means 55CD are synthesized by the beam synthesizing means 56 including, for example, a dichroic mirror.

Further, each beam combining means 5 is selected depending on the characteristics of the laser beam emitted from each laser beam emitting means.
A means for collimating the laser beam and a means for beam-shaping the laser beam are respectively provided in the preceding stages of 5AB and 55CD, and a beam focusing means for focusing the synthesized beam as desired is provided in the subsequent stage of the beam combining means 56. 52 is provided.

[Operation of the Embodiment] The operation of the laser plate making apparatus will be described. FIG. 6 is a block diagram of the main functions of the laser plate making apparatus of FIG. 1 or 4. This block diagram shows the laser drivers 43A to 43D and the semiconductor laser 10A.
It is the same as the conventional block in FIG. 9 except that a plurality of sets of D to D are provided.

FIG. 6 shows the laser beam route A,
A laser plate making apparatus having B, C and D is shown, and semiconductor lasers 10A, 10B, 10C and 10D and a laser driver 4 are shown.
3A, 43B, 43C, 43D are provided.

The mode of concentrating various laser beams such as the simultaneous use of a plurality of laser beams or the alternate use thereof has been described with reference to FIG.
It is performed by the PU 32.

[Effects of the Embodiment] According to the above-described embodiment, the beam intensity is increased by concentrating two, four or more laser beams as compared with the conventional single beam laser plate making apparatus. You can Also,
By using a plurality of laser beams alternately or in sequence, a cooling time can be provided for the laser beams and the life of the semiconductor laser can be extended. Although multiple laser beam sources are used, when irradiating a work piece (resin sheet), they are concentrated into one combined beam, so problems such as joints that have become problems with the conventional multi-beam method Does not occur. Since each optical element is housed in each holder and movable in a predetermined direction, mutual positional adjustment is easy.

[Application to Others, etc.] As described above, this embodiment has been described with reference to the laser plate making apparatus. However,
Also, the laser beam optical system described in FIG. 4 does not have an optical element that is peculiar or limited to the laser plate making device, and this laser beam system has other uses, for example, any measuring device or processing device that uses a laser beam. In the above, it can be adopted as a means for increasing the laser beam intensity.

Therefore, the technical scope of the present invention is not limited to the laser plate making apparatus but can be understood as a laser beam synthesizing apparatus or a laser beam synthesizing method.

[0074]

According to the present invention, there is an advantage that the plate making time can be shortened in the laser plate making apparatus. Further, according to the present invention, it is possible to provide a laser plate making apparatus having a uniform quality finish over the entire printing plate. Further according to the invention,
Generally, a laser beam synthesizing apparatus and a synthesizing method can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a main part of a laser beam optical system of an embodiment of a laser plate making apparatus.

FIG. 2 is a diagram showing a configuration of a laser beam optical system shown in FIG.

FIG. 3A is a block diagram illustrating the concept of the laser beam optical system shown in FIG. FIG. 3 (2) is a diagram showing image formation with different sizes on the resin sheet.

FIG. 4 is a diagram showing a main part of a laser beam optical system of an embodiment of a laser plate making apparatus according to the present invention.

5 is a block diagram illustrating the concept of the laser beam optical system shown in FIG.

FIG. 6 is a diagram for explaining the operation of the laser plate making apparatus that employs the laser beam optical system according to the embodiment of the present invention.

7 is a diagram showing a main part of a laser plate making apparatus adopting the laser beam optical system of FIG.

FIG. 8 is a diagram illustrating an overall configuration of a laser plate making apparatus.

9 is a block diagram illustrating an operation of the laser plate making apparatus shown in FIG.

FIG. 10 is a diagram showing a main part of a laser beam optical system of a conventional laser plate making apparatus.

11 is a diagram showing a configuration of a laser beam optical system shown in FIG.

FIG. 12 is a diagram showing an overall configuration of a laser beam engraving apparatus that has been proposed as a multi-beam type.

[Explanation of reference numerals] 1 plate body 2 resin sheet 4 plate cylinder shaft 5 timing belt 6 pulley 7 plate cylinder rotation motors 10, 10A, 10B, 10C, 10D semiconductor laser 21 optical system 22 rails 23R, 23L bearing 24 Motor for moving laser block 26 Ball screw 27 Mover 28 Laser block mounting base 29 Arm 32 Microcomputer (CPU) 33 Motor driver for moving laser block 35 Motor driver for rotating plate cylinder 38 Data RAM 42 Gamma tables 43A, 43B, 43C, 43D Laser driver 51, 51A, 51B, 51C, 51D Anamorphic prism 52 Objective lens 53 Cover glass 54, 54B, 54D Half-wave plate 55AB, 55CD Polarizing beam splitter 56 Dichroic mirror 60 Collimator lens Holder 61 LD (semiconductor laser) holder 62 LD (semiconductor laser) block 63 Anamorphic prism holder 64 Objective lens holder OA-A, OA-B, OAAB Optical axis

─────────────────────────────────────────────────── ─── Continued Front Page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41C 1/05 B23K 26/06 G03F 7/20 505 H01S 3/10

Claims (9)

(57) [Claims] 1. First and second laser beam emitting means having a wavelength λ1, first birefringent means for rotating the plane of polarization of the laser beam from the second laser beam emitting means, and first First combining means for combining the laser beam from the laser beam emitting means and the laser beam from the birefringent means, and further third and fourth laser beam emitting means having a wavelength λ2 different from the wavelength λ1. Second birefringent means for rotating the plane of polarization of the laser beam from the fourth laser beam emitting means, laser beam from the third laser beam emitting means and laser from the second birefringent means A laser beam provided with a second combining means for combining the beam and a third combining means for combining the laser beam emitted from the first combining means with the laser beam emitted from the second combining means. Beam synthesis device. 2. First and second laser beam emitting means having a wavelength λ1, first and second collimator means for collimating the laser beams from the first and second laser beam emitting means, respectively. First and second beam shaping means for shaping the laser beams from the first and second collimator means, respectively, and a first compound for rotating the polarization plane of the laser beam from the second laser beam emitting means. A refracting means, a first combining means for combining the laser beam from the first beam shaping means and the laser beam from the first birefringent means, and a third wavelength having a wavelength λ2 different from the wavelength λ1. And fourth laser beam emitting means, third and fourth collimator means for collimating the laser beams from the first and second laser beam emitting means, respectively, and the third and fourth Third and fourth beam shaping means for respectively shaping the laser beams from the collimator means, second birefringence means for rotating the polarization plane of the laser beam from the fourth laser beam emitting means, and third Second combining means for combining the laser beam from the beam shaping means and the laser beam from the second birefringence means, and the laser beam emitted from the first combining means and the second combining means. A laser beam synthesizing apparatus comprising: a third synthesizing means for synthesizing emitted laser beams; and a lens means for focusing the laser beam from the third synthesizing means. 3. The laser beam synthesizing apparatus according to claim 2, wherein each of the first, second, third and fourth laser beam radiating means is a semiconductor device. Each of the third and fourth collimator means comprises a collimator lens, each of the first, second, third and fourth beam shaping means comprises an anamorphic prism, and the first and second Each of the birefringent means is a half-wave plate, each of the first and second combining means is a polarization beam splitter, the third combining means is a dichroic mirror, and the lens is The means is a laser beam synthesizing device including an objective lens. 4. A laser beam having a wavelength λ1 is emitted from each of two laser sources, the polarization plane of one laser beam is rotated, and the other laser beam and the laser beam whose polarization plane is rotated are combined. A laser that combines laser beams, emits laser beams with wavelengths λ2 different from each other from two laser sources, rotates the polarization plane of one laser beam, and rotates the polarization plane of the other laser beam. A laser beam synthesizing method including the steps of synthesizing a beam and a synthetic laser beam having a wavelength λ1 and a synthetic laser beam having a wavelength λ2. 5. A laser beam having a wavelength λ1 is emitted from each of two laser sources, each of the laser beams is collimated, each of the laser beams is beam-shaped, and the polarization plane of one of the laser beams is rotated. , The other laser beam and the laser beam whose polarization plane is rotated are combined, and the wavelengths λ1 from the two laser sources are combined.
A laser beam with a different wavelength λ2, collimate each laser beam, shape each laser beam, rotate the polarization plane of one laser beam, and rotate the polarization plane of the other laser beam and this polarization plane. A laser beam synthesizing method including the steps of synthesizing a rotated laser beam, further synthesizing a synthetic laser beam having a wavelength λ1 and a synthetic laser beam having a wavelength λ2, and focusing the synthetic laser beam. 6. A laser plate making apparatus comprising: first and second semiconductor laser devices for emitting laser beams each having a wavelength λ1; and first for rotating a polarization plane of a laser beam from the second semiconductor laser device. A half-wave plate, a first polarization beam splitter that combines the laser beam from the first semiconductor laser device and the laser beam from the first half-wave plate, and each has a wavelength λ1. Third and fourth semiconductor laser devices that emit laser beams having different wavelengths λ2, a second half-wave plate that rotates the plane of polarization of the laser beams from the fourth semiconductor laser device, and And a second polarization beam splitter for combining the laser beam from the semiconductor laser device of No. 3 and the laser beam from the second half-wave plate, and the combined laser beam Laser plate making apparatus for forming a forming a recessed portion by irradiating the resin sheet plate a. 7. A laser plate making apparatus, wherein first and second semiconductor laser devices emitting a laser beam having a wavelength λ1 and respective emitted laser beams of the first and second semiconductor laser devices are collimated. The first and second collimator lenses, the first and second anamorphic prisms for beam-shaping the respective output laser beams of the first and second collimator lenses, and the second anamorphic prism A first half-wave plate that rotates a plane of polarization of a laser beam, a first laser beam from the first anamorphic prism, and a laser beam from the first half-wave plate. Polarization beam splitter, and third and fourth semiconductor laser devices for emitting a laser beam having a wavelength λ2, and the third and fourth semiconductor laser devices. Third and fourth collimator lenses for collimating the respective emitted laser beams of the semiconductor laser device, and third and second collimator lenses for shaping the respective emitted laser beams of the third and fourth collimator lenses, respectively. An anamorphic prism, a second half-wave plate that rotates the plane of polarization of the laser beam from the fourth anamorphic prism, a laser beam from the third anamorphic prism, and the second half Second polarizing beam splitter for synthesizing a laser beam from one wavelength plate, a synthetic laser beam of wavelength λ1 emitted from the first polarizing beam splitter, and a synthetic laser of wavelength λ2 emitted from the second polarizing beam splitter A dichroic mirror that synthesizes the beam and a synthetic laser that emits from the dichroic mirror. And an objective lens for focusing the beam, the laser plate making apparatus for forming a printing plate by forming a concave portion irradiated with the focused combined laser beam to the resin sheet. 8. In the laser plate making method, first and second laser beams having a wavelength λ1 are emitted, the plane of polarization of the second laser beam is rotated, and the plane of polarization of the first laser beam is rotated. A third beam having a wavelength λ2 different from the wavelength λ1 combined with the laser beam
And radiating a fourth laser beam, rotating the plane of polarization of the fourth laser beam, synthesizing the third laser beam and the laser beam having the plane of polarization rotated, and synthesizing the synthesized laser beam of wavelength λ1 and the wavelength A laser plate making method comprising the steps of synthesizing a synthetic laser beam of λ 2 and irradiating the resin sheet to form recesses to form a printing plate. 9. A laser plate making method, wherein first and second laser beams having a wavelength λ1 are radiated, said first and second laser beams are collimated, and said first and second laser beams are produced. Beam shaping is performed respectively, the polarization plane of the second laser beam is rotated, the first laser beam and the laser beam whose polarization plane is rotated are combined, and the third laser beam having a wavelength λ2 different from the wavelength λ1 is further synthesized.
And a fourth laser beam is emitted, the third and fourth emitted laser beams are collimated, the polarization plane of the fourth laser beam is rotated, and the third laser beam and the polarization plane are rotated. The laser beam is combined, the combined laser beam of wavelength λ1 and the combined laser beam of wavelength λ2 are further combined, and the combined laser beam is focused and irradiated onto the resin sheet to form a recess to form a printing plate. A laser plate making method including steps.